Auxiliary steering and propulsion unit



Oct. 2, 1962 H. D. LINHARDT AUXILIARY STEERING Am PRoPULsIoN UNIT FiledMaren 2e, 1959 5 Sheets-Sheet l INV ENTOR.

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AUXILIARY STEERING AND PROPULSION UNIT Filed March 26, 1959 3Sheets-Sheet 2 M @www @frag/5% Oct. 2, 1962 H. D. I INHARDT 3,056,374

AUXILIARY STEERING AND PROPULSION UNIT Filed March 26, 1959 3Sheets-Sheet 3 HQNS D. UNH/67,907,

INVENTOR.

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3,056,374 AUXIELEARY STERREN@ AND PRPULSiQN UNET Hans D. Linirrdt, 2h33N. Beachwood Drive, i-loliywood 25, Calif. Filed Mar. 2e, i959, Ser. No.SliZalSl 4 Claims. (Qi. lid- 315D This invention relates to a turbinepump driven auxiliary steering and propulsion unit which in a preferredform of the invention is mounted on the rudder blade of a ship. inanother form of the invention as exemplified herein, the auxiliarysteering and propulsion unit may be mounted in the bow of a ship toprovide a transverse reaction thrust. The purpose of the invention is toprovide improved steering qualities and improved maneuverability.

The problem of steering a ship at slow speed is an old one and has notbeen adequately or satisfactorily solved in the prior art. A practicalsolution of the problem is necessary for all vessels operating in narrowwaters, canals or locks, especially in strong winds, currents and goingin ballast and by seagoing ships in high seas and storms. ln suchoperations the normal rudder is unsatisfactory as the induced forces onthe rudder blade are too weak to induce sufficient steering power.Necessarily the helm angle has to be increased for the necessaryreaction on the ship, resulting in an overreaction or overcontrolling toone side or the other so that the ship yaws and loses speed andotherwise does not navigate satisfactorily.

A practical and efficient steering device has been necessary which doesnot depend on a current produced by the ships propeller or the shipsmovement but which is effective when the ship has no way on and is ableto turn the Vessel on the spot or in very small circles.

Having in mind the rather severe requirements for a practical andadequate solution of the problem, there has been conceived a uniqueauxiliary steering and propulsion unit having a pump turbine drive, theturbine being mounted on the rudder and powered by hydraulic Huid underpressure which may be sea water provided by a service pump on the ship.The particular u nit overcomes the drawbacks attendant to attempts touse other types of drive and more particularly that the unit provides anadequately flexible and eiiicient power supply for the auxiliarypropeller. The particular unit provided results in a most economicalspeed and power control of the auxiliary propeller covering a largerange of desirable operating points. in one form of the invention avariable pitch propeller is provided which in fact results in an optimumpropulsion system.

The main objective of the invention is accordingly to solve the problempractically and adequately of steering a ship at slow speed and inrestricted waters. More particularly it is an object of the invention toprovide a unique auxiliary steering and propulsion unit which overcomesthe drawbacks attendant to prior art attempts to solve the problem andwhich provides an appropriately flexible efficient, practical andeconomical steering unit.

A further object of the invention is to realize the advantages andresults inherent in the following explanation.

The main effect of the auxiliary steering device is that there is alwaysa thrust in the direction of the rudder and therefore an active ruddermoment. The effect has been demonstrated by plotting the maneuverabilityof a particular ship with and without a steering and propulsion unit.r[he maneuverability was plotted in terms of the radius of the shipsturning circle as respects speed. The advantage of the unit is obviousfor slow speed operations. The entire rudder thrust can be reversed irnmatenteti c't. 2, i962 mediately by a suitable power control orpropeller design. Therefore the rudder does not have to be turned fromhard port to hard starboard. The turning motion of the ship in rotationcan also be stopped and lreversed within a short time. Special maneuverscan be carried out with the propeller of the auxiliary unit runningahead or astern, the main engine stopped or running slightly ahead orreverse. Such maneuvers are especially of interest for surveying ships,which are in need of a perfect maneuverability, remaining perfect atslow speeds and with the ship not under way. During measurements callingfor an exactly i'ixed position with the ship not under way it isnecessary to counterbalance all wind and current forces within the wholerange of the same. With increasing wind forces and sea the thrust of theauxiliary unit has to be increased as well as the rudder angle. Thethrust may be controlled by a variable pitch propeller or by means ofthe speed of the power source or both. Usually such conditions require atwin screw ships propulsion which is very uneconomical, both mainengines working against each other to eliminate any forward or backwardmotion of the ship.

in addition to realization of the foregoing advantages, a further objectof the invention is to stabilize the flow of water around the rudderblade by means of the auxiliary propeller. The ow behind the mainpropeller can be improved by the suction of the auxiliary unit mountedin line with the main screw. Mainly the dead Water region of the mainpropeller is improved near the hub and the contraction of the leavingjet can be avoided to some amount. The propulsion efficiency itself isimproved by the propulsion body surrounding the power unit.

Another object of the invention utilizing a turbine for the auxiliaryunit of a mixed llow type having a high leaving velocity is to partlyrecover the energy of the high leaving velocity at the auxiliarypropeller located at the turbine exit.

Another object of the invention is to achieve highly flexible andeficient control by way of speed control of the service pump or byhydraulic control of the service pump which supplies highly energizedfluid to the auxiliary turbine.

Another object of the invention is to relieve the load on the thrustbearings of the auxiliary turbine by balancing the propeller thrustagainst the turbine thrust.

in a slightly modied form of the invention two turbines are utilizedrotating in the same direction and having concentric shafts. Twoauxiliary propellers are provided rotating in the same direction, theiirst serving as an inducer to suppress cavitation and the second as ahigh speed propulsion device. Both propellers are surrounded by a nozzlefor protection as well as the design approach of an impulse pump. Theinducer propeller runs in a direction opposite to that of the main screwrecovering some part of the energy furnished by the wake of the mainpropeller. Another object of the invention is to achieve and realize theresults as stated inherent in the aforesaid modified form of theinvention.

For some ships the auxiliary steering and propulsion unit as describedin the foregoing mounted in the rudder blade is not suicient to providethe required maneuverability in small channels, locks or harbors. Suchsteering qualities are very important for war ships in dangerous areas.Prior art attempts to solve the problem have failed to give a solutionwhich does not decrease the overall performance of the ship during fullcruising speed. Another form of the herein invention provides a solutionto the problem preferably by way of a transverse bow channel through theship having means to produce a suitable reaction thrust in the channelfor steering `and maneuvering. Model tests have been carried outinvestigating arredare different forms of bow channels and it has beenfound that very useful and surprising Steering qualities can be achievedwith a straight channel as exemplified herein during high speed. Duringslow speed the reaction of the Water jet is used for turning; duringhigh speed resistance of the water jet provides turning moment in thedirection of the leaving water jet. A further object of the invention isaccordingly to provide additional required maneuverability by means of achannel preferably at the bow in which a transverse reaction thrust ispro-- duced.

Y Further objects and numerous detailed additional advantages of theinvention will become apparent from the following detailed descriptionand annexed drawings, wherein:

FIG. l is a partial diagrammatic view of the stern of a ship having apreferred form of the herein invention embodied therein;

FIG. 2 is a partial Sectional View in detail of the auxiliary steeringand propulsion unit of FIG. l;

FIG. 3 is a diagrammatic view of a modified form of auxiliary steeringand propulsion unit;

FIG. 4 is a diagrammatic view of the bow of a ship having a modied formof the invention embodied therein;

FIG. 5 is a sectional View taken along the line 5-5 of FIG. 4;

FIG. 6 is a diagram or graph of thrust versus velocity for the type ofinstallation shown in FIGS. 7 and 8;

FIG. 7 is a diagrammatic illustration of the steering effect of a unit`as shown in FIG. 5;

FIG. 8 is a similar diagrammatic illustration showing the effect ofreversing the direction of flow through the unit at higher speeds;

FIG. 9 is a diagrammatic view of the ship showing the surface of theWater relative to the steering unit at relatively low speeds;

FIG. 10 is a view similar to FIG. 9 showing the water surface at higherspeed; and

FIG. ll is a chart similar to that of FIG. 6 showing the effect on thethrust resulting from increasing the speed of the unit or otherwiseincreasing the thrust at low velocity of the ship.

FIG. l of `the drawings shows the stern part of a ship diagrammaticallyat 10. The main propeller of the ship is designated at lll just ahead ofthe rudder designated at 12. The rudder is on a rudder post 13 and theauxiliary steering and propulsion unit of the invention is designated at16. The propulsion unit is in a faired or streamlined housing in therudder in order to offer a minimum of hydrodynamic resistance. As willbe explained hereinafter, the turbine unit is powered from the servicepump on board the ship which supplies highly energized sea water to theturbine unit. The service pump itself is not shown in FIG. 1.

FIG. 2 shows part of the rudder 12 and the auxiliary steering andpropulsion u nit in cross section.

The rudder 12 is essentially of standard type having a built upconstruction as shown including the internal struts and rib members ll7and 1S. The rudder itself, preferably has a faired or streamlinedconfiguration to reduce hydrodynamic resistance. The auxiliary steeringand propulsion turbine as designated at is supported from internalstructure 21 within the rudder and part of which is within the body 16of the auxiliary unit.

The turbine 20 is of a mixed in-flow type, its thrust being -balancedagainst the thrust of the propeller which it drives. The turbine shaftis designated at 22, the shaft being journaled in bearings adjacent theends of the shaft as indicated diagrammatically at 23 and 24. Theturbine casing is indicated at 26 and it of course carries the turbinestator yor stator parts. Numeral 27 designates an inlet box which is inthe form of an involute at the right end of the turbine stator and thisinvolute communicates with an inlet pipe 30 for high pressure hydraulicfluid. The pipe or conduit 30 extends upwardly through the rudder sternwhich is hollow. As described, the conduit 30 connects with the servicepump on board the ship.

The turbine has a closing housing 3l at the right end within which isdisposed a thrust bearing comprising the disc 32 on shaft 22. The disccarries thrust ring elements 33 and 34 which cooperate with ring shapedthrust members 35 and 36 made of appropriate material.

At the right end of the shaft 22 is a variable pitch or pitch reversingunit 37 by which the pitch of the auxiliary propeller may be varied.This unit is of a type known to the art and may be controlled forexample by Way of hydraulic fluid connections as shown at 40 and 41.

The turbine includes stator member 42 fixed to the casing and rotormember 43 on the shaft 22. As stated the turbine is of an ineflow type;highly energized hydraulic fluid from the involute 27 feeds to the rotor43 at its periphery, the rotor having suitable vanes as shown. r[hefluid passes from the central portion of the rotor 43 outwardly asguided by a stator member or portion 45. The uid then flows inwardly asrespects rotor 47 between this rotor and stator member 48. The flow isthen again outwardly adjacent stator portion 50' and inwardly asrespects rotor member 5l. The shaft 22 rotates in appropriate bearingscarried by the stator portions 45 and Sil.

The turbine has an exhaust section as indicated at which is diverging asshown, having a diverging annular exhaust channel as shown at 56. Theexhaust section is suitably supported in the turbine casing and providesa bearing for the shaft 22 as shown diagrammatically. The section 55 hasan extending skirt as shown at 57 which terminates adjacent thepropeller hub 58. The hub includes a disc S9 attached to the end of .theshaft 22 by means including a ange as shown at 60. Numeral 64 designatesstruts supporting the nozzle 63. The nozzle 63 is of faired orstreamlined configuration to reduce hydrodynamic resistance and is ofbuilt-up construction as shown comprising the sections 65 and 66. Nozzle68 produces some thrust according to its angle of attack.

In operation the turbine unit as described is supplied with highlyenergized hydraulic fluid such as sea Water from the service pump in theship through the conduit 30. Thus a rugged and simple power supply isprovided susceptible to effective speed control by a speed control ofthe service pump or by hydraulic control of the pump such as by inletvane or valve control. The direction of propeller thrust may be reversedby changing the pitch of the propeller 61 by means of the variable pitchdevice 37. This therefore may be used in steering and maneuvering in themanner discussed in the introduction. The thrust bearings are nearlyWithout load because the propeller thrust is balanced against `theturbine thrust as may be seen from FIG. 2. The turbine has a relativelyhigh leaving velocity and part of this energy is recovered by theauxiliary propeller 61 at the turbine exit. The turbine bearings are-water lubricated, water being admitted by way of the channel as shownat 68.

The torque characteristics of a system as described have been analyzedand are highly appropriate to meet the requirements. The system makespossible the use of the maximum torque most effectively for properstarting under any conditions. The system provides an economical andhighly effective steering and propulsion unit which minimizes size andweight but yet offers optimum flexibility.

The speed of a unit of the type described is mainly xed by cavitationconsiderations. By using anti-cavitation techniques higher propellerspeeds may be provided resulting in smaller dimensions, decreasedhydrodynamic drag, or a desirable increase in power and thrust. Theefficiency of the unit described is high; at some sacrifice inehciencies higher propeller speeds may be utilized, making it possibleto reduce the dimensions of the unit and thereby reducing the drag, thatis, the hydrodynamic resistance of the turbine housing. This result isrealized in a modified form of the invention shown in FIG. 3.

In FIG. 3 the rudder is shown at 72 with a turbine pump steering andpropulsion unit or units designated generally at 73. There are eithertwo turbines or a twostage turbine having concentric shafts as shown at74 driving two propellers 75 and 76 at dierent speeds. The inlets to theturbines are shown at 77 and 78, the drive corresponding otherwise tothat of the previous embodiment. The propellers rotate within a nozzle81 which iS connected to the body 73 of the unit by strut members asshown at 82.

The unit is mounted on the rudder directly astern of and aligned withthe main propeller shaft as shown in FIG. l.

Propellers 75 and 76 rotate in the same direction; however propeller 75serves as an inducer to suppress cavitation astern of the main shipspropeller. The second propeller 76 acts as a high speed propulsiondevice. The propeller 75 might utilize 25%, for example, of theavailable power. The inducer propeller 75 operates in the:

opposite rotational direction from the main propeller and recovers somepart of the energy furnished by the wake of the main propeller. Thisform of the invention accordingly provides a unit utilizing a higherpropeller speed, in which cavitation is suppressed and the overall sizeof the unit being smaller to lessen the drag. Two lightly loadedcounter-rotating propellers may also be used.

FIGS. 4 and 5 show another form of the invention exemplifyingapplication of its principles in a slightly different way. In FIG. 4there is shown diagrammatically the bow or forward part of a ship havinga transverse ow channel S5 therein which is shown more in detail in FIG.5. In FIG. 5 there is shown in cross section the lower part of the hull86 of a ship. The ship has decks as shown at S7 and 88 and watertightcompartments as shown. The channel 85 is preferably near the bow of theship but not necessarily so. This channel is formed to be extendingtransversely of the hull of the ship as shown and structurally may bebuilt in any appropriate manner using structural techniques alreadyknown in the art. 'Ihe keel or bilge of the ship is shown at 91 and asshown in FIG. 5 control means are provided at the. end of the channel 85in the form of adjustable louvres as shown at 92. The louvres 92 may beadjusted by means of any suitable and appropriate steering controlapparatus already known in the art.

Mounted in the channel 85 is a turbine pump or thrust producing unit asshown at 94 which may preferably be of the type shown in FIG. 2. It isto be understood how ever that other types of thrust reaction unitsmight be utilized in the channel S5.

The form of the invention as shown in FIGS. 4 and 5 is useful to providethe required maneuverability in small channels, locks or harbors. Suchsteering qualities are very important for war ships in dangerous areas.Tests have shown that the type of channel as shown in FIGS. 4 and 5performs highly successfully. Speed control of the turbine or the likeand a variable pitch propeller may be utilized as discussed inconnection with the previous ern bodiments. The channel 85 may also becurved downward or toward or against the ow direction that is the ow ofwater passing the ship. Very useful and surprising steering qualitiescan be achieved with a straight channel as shown in FIGS. 4 and 5 whenoperating at high speed. The auxiliary propeller operates heavily loadedduring low speeds of advance. Preferably the propeller or propellersused are of a type combining a pump and propeller concept to operateefficiently at lower speeds. The principle of the invention however andits actual practical application are fully illustrated in FIGS. 4 and 5taken with the herein description.

FIGS. 6 to ll illustrate the useful and surprising steering qualitiesthat can be realized with the channel as shown in FIGS. 4 and 5 whenoperating at high speed.

FIG. 7 illustrates diagrammatically the bow of a ship 86 having astraight transverse channel 85 with a unit 94 therein which may forexample be of the type shown in FIG. 2. FIG. 7 illustrates the flow ofwater past the ship and the flow of water through the channel when theship or vessel is moving at a relatively low velocity V. The velocity ofthe water through the channel 85 is indicated by v. The ilow of waterthrough the channel is indicated by the arrow and the direction of thethrust which produces steering moment is indicated by T. FIG. 7 alsoindicates the general direction of movement of water entering andleaving the channel 85. These conditions as represented are forrelatively low velocities of the ship.

FIG. 6 is a chart or graph of velocity of the ship versus thrustproduced by the unit 94 as shown in FIG. 7. As may be seen in FIG. 6 asthe velocity of the ship increases at a given power of the unit 94 thethrust at a certain point as shown drops off rather abruptly and in factwill drop to zero `as shown. This effect has been discovered in actualtest and it is a part of this invention, knowing this condition toreverse the direction of iiow through the channel 85 at or substantiallyat the zero point as illustrated in FIG. 8 and as further illustrated inthe graph FIG. 6. As shown in FIG. 8 the flow of water through thechannel 85 has been reversed the ship 86 now moving at a relativelyhigher velocity. The effect now is that the water leaving the channel 85jets out into the sea and actually has the effect of a steering memberbeing thrust out in that direction. In other words the thrust T remainsin the direction shown in FIG. 8 after reversing the direction of flowthrough the channel 85. The reversal of the direction of ow may ofcourse be achieved by reversing the direction of rotation of the unit94.

FIGS. 9 and l0 illustrate diagrammatically the surface of the water asrespects the bow of the ship when the ship is moving at relatively lowspeed as shown in FIG. 9 and at relatively higher speed as shown in FIG.l0. As shown in FIG. l0 at the higher speeds the surface of the Waterhas the general shape shown tending to form a depression or cavity aftof the channel S5. From this the effect described in FIG. 8 can beunderstood.

It may of course be desirable to not allow the thrust T or steeringmoment drop all the way to zero. This may be accomplished of course withreference to FIG. 7 by for example speeding up the unit 94 before thezero thrust point is reached as is illustrated in the chart or graph ofFIG. ll. Thus as shown the thrust is not allowed to drop to `zero butrather the curve has a horizontal low portion as shown in the figure.

In regard to FIGS. 6 to ll different types of units may of course beused in the channel 85 and the desired control effects may be achievedby reversals in direction of rotation, changes in speed or changing thepitch of the propeller or propellers of the unit 94. The ends of thechannel 85 may be controlled by flaps or louvers 92 as shown inconnection with FIG. 5.

From the foregoing those skilled in the art will observe that the formsof the invention disclosed are practical embodiments thereof which inthe manner explained achieve and realize the results, objectives andadvantages heretofore outlined. The invention solves a problem and meetsa need which has not heretofore been practically or adequately met.

The foregoing disclosure is representative of preferred forms of theinvention and is to be interpreted in an illustrative rather than alimiting sense. Various modifications and alternatives may occur to andbe adopted by those skilled in the art, all within the realm and spiritof the invention, which is to be accorded the full scope of the claimsappended hereto.

What is claimed is:

l. In combination with a propeller and steering member attached to aship, an auxiliary steering and propulsion unit comprising a uid poweredaxial 110W turbine carried by the steering member and a propeller drivenby the turbine, positioned to have the turbine discharge through it.

2. The combination of claim 1 wherein the said auxiliary unit is mountedon the steering member in a position such that in mid-position of thesteering member the auxiliary unit is directly astern of and alignedwith the driving propeller of the ship.

3. The :combination of claim 1 including nozzle means positioned aroundthe said propeller driven by the turbine.

4. The combination of claim 1 including means for varying the pitch ofthe propeller driven by the said turbine. l

References Cited in the le of this patent UNITED STATES PATENTS PrattMay 19, 1931 Cogswell Oct. 13, 1942 Briggs Sept. 28, 1943 Katcher et alNov. 21, 1944 Frasure Oct. 27, 1953 Waterval Oct. 16, 1956 SWan Sept. 2,1958 OTHER REFERENCES The British Motor Ship, September 1952, page 239.

